Protein
calculator.
Turn your body weight into grams of protein a day, using the reference you choose: the RDA, the U.S. Dietary Guidelines goal, or the sports-nutrition ranges for people who train. See every reference side by side, split it across your meals, and check its share of your calories.
At 70 kg, the RDA of 0.8 g/kg is 56 g of protein a day, or 14 g at each of 4 meals.
- Protein a day
- 56 g
- Per kg of body weight
- 0.8 g/kg
- Per pound of body weight
- 0.363 g/lb
- Per meal (4 meals)
- 14 g
- Calories from protein
- 224 kcal
- Share of 2,200 kcal
- 10.2%
protein = 70 kg × 0.8 g/kg = 56 g; calories = grams × 4 kcal/g = 224 kcal; per meal = ÷ 4 = 14 gGrams per kilogram,
not guesswork.
- Protein a day = body weight in kg × a reference intake in g/kg. Pounds are converted at exactly 1 lb = 0.45359237 kg.
- RDA (Dietary Reference Intakes): 0.8 g/kg for adults 19 and over, 0.85 at 14–18, 0.95 at 4–13 and 1.05 at 1–3; 1.1 g/kg in the second half of pregnancy and 1.3 g/kg while breastfeeding.
- Dietary Guidelines for Americans, 2025–2030: 1.2–1.6 g/kg a day. ISSN position stand: 1.4–2.0 g/kg for most exercising people, and 2.3–3.1 g/kg for resistance-trained people in a calorie deficit.
- Calories from protein use 4 kcal per gram. The per-meal figure divides the daily amount evenly; ISSN suggests about 0.25 g/kg per serving.
- Nothing is rounded until display; grams are shown to the nearest gram and the formula to two decimals. It uses total body weight, as the sources do.
How do you calculate how much protein you need a day?
Multiply your body weight in kilograms by a protein intake in grams per kilogram. The Recommended Dietary Allowance for adults is 0.8 g/kg, so a 70 kg adult needs 70 × 0.8 = 56 g a day to meet the RDA. At 4 kcal per gram that is 224 kcal, about 10% of a 2,200 kcal day. The RDA is set to cover the needs of nearly all healthy people; it is a reference for adequacy, not a target for athletes.
protein (g/day) = weight (kg) × intake (g/kg/day)
weight (kg) = weight (lb) × 0.45359237How much protein do the 2025–2030 Dietary Guidelines recommend?
The Dietary Guidelines for Americans, 2025–2030 set a protein goal of 1.2–1.6 grams per kilogram of body weight a day, adjusted to your calorie needs, and advise including protein foods at every meal. For a 150 lb person (68.04 kg) that is 68.04 × 1.2 = 81.6 g to 68.04 × 1.6 = 108.9 g, or 82–109 g a day. Split across three meals, it is about 27–36 g a meal. The RDA of 0.8 g/kg in the Dietary Reference Intakes is unchanged; the Guidelines’ range is higher.
How much protein do you need if you lift weights or train?
The International Society of Sports Nutrition’s position stand says 1.4–2.0 g/kg a day is sufficient for most exercising people to build and maintain muscle. An 80 kg person who trains would aim for 80 × 1.4 = 112 g to 80 × 2.0 = 160 g a day, or 28–40 g at each of four meals. For resistance-trained people eating below maintenance, the same paper says 2.3–3.1 g/kg may be needed to keep lean mass: 207–279 g a day at 90 kg.
How much protein should you eat per meal?
Divide the daily amount by your meals. The ISSN position stand gives a general per-serving figure of 0.25 g of high-quality protein per kg of body weight, or 20–40 g, spread evenly every 3–4 hours. At 80 kg, 0.25 g/kg is 20 g; 160 g a day over four meals is 40 g each, the top of that range. The calculator shows both: your even split and the 0.25 g/kg dose.
How much protein do you need when pregnant or breastfeeding?
The Dietary Reference Intakes set an RDA of 1.1 g/kg a day for the second half of pregnancy and 1.3 g/kg a day while breastfeeding. In the first half of pregnancy, needs are the same as for a woman who is not pregnant. At 65 kg, 65 × 1.1 = 71.5 g a day in the second half of pregnancy. These are population references; your clinician or midwife can advise on your own needs.
What percentage of calories should come from protein?
The Acceptable Macronutrient Distribution Range for adults is 10–35% of calories from protein. Enter your calories and the calculator converts grams to kcal at 4 kcal/g and shows the share. 279 g at 4 kcal/g is 1,116 kcal, which is 46.5% of 2,400 kcal, above that range. To split all three macronutrients, use the macro calculator.
Worked examples.
Adult RDA
A 70 kg adult, four meals, 2,200 kcal a day, using the RDA.
56 g a day: 14 g at each of 4 meals, 224 kcal, 10.2% of calories.
Load this exampleDietary Guidelines range in pounds
150 lb, three meals, the 2025–2030 Dietary Guidelines goal of 1.2–1.6 g/kg.
82–109 g a day, or 27–36 g at each of 3 meals.
Load this exampleStrength training
An 80 kg person who trains, building or maintaining, four meals.
112–160 g a day: 28–40 g at each of 4 meals; ISSN’s 0.25 g/kg dose is 20 g.
Load this exampleLifting during a calorie deficit
90 kg, resistance-trained, eating 2,400 kcal, five meals.
207–279 g a day, 34.5–46.5% of calories: the top is above the 35% range.
Load this exampleSecond half of pregnancy
65 kg, the RDA for the second half of pregnancy, three meals.
72 g a day (71.5 g): 1.1 g/kg, about 24 g a meal.
Load this exampleChecking your own figure
160 lb adult, your own 1.0 g/kg, three meals, 2,000 kcal.
73 g a day, 14.5% of calories; above the 58 g RDA.
Load this exampleWhat this calculator
does not do.
- These are population references for healthy people, not an individual prescription. People with kidney or liver disease, other medical conditions, or who are pregnant should get advice from a clinician or dietitian.
- It uses total body weight, as the RDA, the Dietary Guidelines and the ISSN figures are written. It does not adjust for body composition or for a goal weight.
- The Dietary Guidelines and ISSN ranges are for adults; for children and pregnancy only the RDA by life stage is offered.
- It counts grams of protein only, not protein quality, digestibility or the amino acid mix of your foods.
Common questions.
How many grams of protein do I need a day?
At least 0.8 g per kg of body weight for adults (the RDA): 56 g at 70 kg. The 2025–2030 Dietary Guidelines set a goal of 1.2–1.6 g/kg, 84–112 g at 70 kg.
How much protein is that per pound?
Divide by 2.2046. 0.8 g/kg is about 0.36 g per pound; 1.6 g/kg is about 0.73 g per pound; 2.0 g/kg is about 0.91 g per pound.
How many calories are in a gram of protein?
4 kcal, the general factor used on U.S. nutrition labels. 100 g of protein supplies about 400 kcal.
Is the RDA enough if I exercise?
The RDA covers the needs of nearly all healthy people. For exercising people, the ISSN position stand recommends 1.4–2.0 g/kg a day, and higher in a calorie deficit for those who lift.
Should I use my current weight or my goal weight?
The sources express intakes per kg of body weight, and this calculator uses the weight you enter. If you are unsure which weight suits you, ask a dietitian.
- Health Canada: Dietary Reference Intakes tables, reference values for macronutrients — protein RDA in g/kg/day by life stage (0.80 adults, 1.1 pregnancy, 1.3 lactation); pregnancy value for the second half only; AMDR 10–35% protein
- National Academies: report on energy and macronutrients (2002) — reaffirms the protein RDA of 0.8 g per kg of body weight for adults; adult range 10–35% of calories from protein
- USDA and HHS: Dietary Guidelines for Americans, 2025–2030 — protein serving goals of 1.2–1.6 g per kg of body weight per day, adjusted to calorie needs
- Jäger R, et al. ISSN Position Stand: protein and exercise. J Int Soc Sports Nutr 2017;14:20 (PMC5477153) — 1.4–2.0 g/kg/d for most exercising people; 2.3–3.1 g/kg/d in hypocaloric periods; 0.25 g/kg or 20–40 g per serving every 3–4 h
- 21 CFR 101.9(c)(1)(i), nutrition labeling of food — general factors of 4, 4 and 9 calories per gram for protein, carbohydrate and fat
Grams are body weight in kg times the chosen g/kg, with pounds converted at the exact 0.45359237 kg. The calculation is plain multiplication with no rounding until display. Our tests check six worked cases computed by hand, every life stage and reference against the source tables, 300 seeded random cases for unit round trips (kg and lb give the same grams), linearity in weight and meals, the calorie share, and validation of every field.
Built and reviewed by CalculatorLab against the sources above; every worked example on this page is re-checked by our automated test suite before each release. How we build and check calculators. Found a problem? Tell us.